The invention relates generally to wind turbines, and more specifically to use of a plasma actuator that operates without an external source of air other than ambient air to modify wind turbine boundary layer separation to energize retarded flows and to reduce the collection of ice over wind turbine blades.
Boundary layer separation takes place over highly curved surfaces for flows at high-angles of attack. This characteristic contributes to loss of pressure and hence a decline in aerodynamic efficiency of a wind turbine. In cold areas, collection of ice on the wind turbine blades not only contributes to loss of pressure, but also is hazardous.
Different techniques have been employed to modify the boundary layer interaction to control flow characteristics. Many of these well known techniques use passive methods and devices, while some others use piezo electric surface modifications for flow control. One known technique employs Dielectric Bather Discharge (DBD) devices to modify boundary layer interaction to control flow characteristics associated with an air induction system for an aircraft. Another known technique employs surface cavities to modify the boundary layer growth to mitigate flow losses.
Currently, there are no techniques used to overcome boundary-layer separation and simultaneously deice wind turbine blades. Vortex generators have been used to passively delay flow separation; but a major disadvantage to this solution is the vortex generator enhanced flow, even in situations where delaying flow separation is no longer desired.
In view of the foregoing, it would be advantageous to provide a method to actively control flow separation and deice wind turbine blades. The method would employ a plasma actuator that is compact with no exposed moving parts, that operates without an external source of air other than ambient air, that requires little power to operate, that provides more versatility than passive techniques, and that can be applied to existing devices such as, without limitation, fan blades and turbine blades, with only minor modifications(s).